add support for oauth2 with preregistered token

[rampaq]

Issue #954 for OAUTH2 support.

[hchasens]

Making cyrus-sasl-xoauth2-git a dependency might be an issue. If you're not on Arch than you don't have access to the AUR. Without it, installing cyrus-sasl-xoauth2-git requires building it from source. It's documentation doesn't list which dependencies it needs which makes the process even more difficult. I think OAUTH2 is important. Maybe if it's packaged outside of the AUR?

[rampaq]

I think there might be other alternatives providing sasl-xoauth2 as suggested by Arch Wiki but I haven't found any: https://wiki.archlinux.org/title/isync#Using_XOAUTH2

[rampaq]

Also, I haven't tested the code very throughougly as I have a quite custom mutt setup conflicting with auto-management by mutt-wizard.

[hchasens]

I definitely think OAuth is worth pursuing. I tested your fork on Fedora. Due to the difficulties setting up the dependencies, I found it much easier to just manually configure OAuth without the wizard. If we can figure out the dependency issue though, this'll add a good layer of security and usability.

[rampaq]

Thanks for testing! What do you mean by

I found it much easier to just manually configure OAuth without the wizard.

Do you mean that you needed debugging messages during the setup process from to pinpoint problems with the dependencies?

[rampaq]

I have missed a mbsync config for OAUTH support. That is fixed now and conflicts with master branch resolved.